The present invention relates to plastic tampon applicators which are readily disposed in a sewage system and/or by biodegradation. In particular, the present invention relates to flushable tampon applicators which are made from thermoplastic materials that are suitable for rapid disposal in a toilet system.
Feminine hygiene products such as tampons are commonly used by female consumers. Tampons can be described as a feminine hygiene article that has an absorbent device (i.e., pledget) withheld in a paper or plastic applicator.
Paper and plastic tampon applicators typically comprise an outer tubular member and a plunger for insertion of the pledget, whereby these components of the paper and plastic applicators are generally made from paper, paper coated, and plastic materials which retain their form during use and are shelf-stable under ambient conditions.
In addition to absorbent pledget devices, paper tampon applicator components are suitable for disposal via a sewage system or by biodegradable waste disposal means. Therefore, paper tampon applicators are considered environmentally friendly in that these paper tampon applicators can readily disintegrate in a sewage system and/or can be disposed of through aerobic, anaerobic, and natural degradation processes. However, paper tampon articles are not very popular among females due to some tampon""s pledget insertion difficulties associated with the use of a paper tampon applicator.
Certain female consumers prefer plastic tampon applicators because the plastic applicators are made with a grip ring and petal-shaped forward end which facilitate ease of insertion of a tampon""s pledget, although plastic tampon applicator components are not easily disposed of as compared to paper applicator components. Most plastic tampon applicators are made from polyethylene-based polymeric materials that are not biodegradable and that do not readily soften or break-up into smaller fragments for decomposition in a sewage system, resulting in increased environmental concerns for the disposal of plastic tampon applicators.
Many efforts to address the environmental concerns of the disposal of plastic tampon applicators include the manufacture of tampon applicators from thermoplastic materials other than polyethylene polymers. Such attempts include tampon applicators made from water-soluble materials, water-dispersible materials, biodegradable materials, photodegradable materials, ultraviolet light degradable materials, or combinations thereof. In particular, one attempt to address the disposal of plastic tampon applicators involves the use of plastic applicators made from biodegradable polymers such as polyvinyl alcohol polymers. It is known that tampon applicators made primarily from polyvinyl alcohol are water-dispersible and biodegradable, however, such applicators have been shown to suffer from issues involving moisture sensitivity, stability, odor, and stickiness.
Other attempts in addressing the disposal of plastic tampon applicators include plastic tampon applicators made from other water-soluble materials such as polyethylene oxide polymers, thermoplastic starch, and hydroxypropyl cellulose; plastic tampon applicators made from combinations of water-soluble and water-insoluble/biodegradable materials such as combinations of polyvinyl alcohol and polycaprolactone, combinations of polyethylene oxide and polycaprolactone, combinations of polyethylene oxide and polyolefins such as polypropylene and polyethylene; and combinations of polyvinyl alcohol and polyethylene oxide polymers.
An example of a plastic tampon applicator constructed from a combination of polyvinyl alcohol and polyethylene oxide is disclosed in U.S. Pat. No. 5,395,308. This plastic tampon applicator is described as being constructed to exhibit accelerated break-up and rapid disintegration in liquid such as water so that the plastic applicator can dissolve over an extended period of time without causing problems in sewage systems such as a waste treatment facility. The slow dissolution rate of these plastic tampon applicators can lead to the clogging of toilet systems and/or drain pipes because of the extended time required for these plastic applicators to initially come in contact with liquid such as toilet water and eventually reach waste disposal means at a waste treatment facility, especially if multiple plastic applicators are suited for disposal.
Therefore, the need exists for the manufacture of plastic tampon applicators made from thermoplastic materials that are flushable and can not only readily lose their structural integrity as for example breaking apart in unrecognizable pieces in a sewage system such as a toilet, but that can readily soften, disperse, disintegrate, and/or dissolve in a toilet for clear passage through the toilet to a municipal waste treatment facility. The tampon applicator components should also be anerobically and/or aerobically biodegradable, as well as provide for a flushable tampon applicator that is not slimy, sticky, or tacky to the touch before and during use.
The present invention is directed to flushable tampon applicators which comprise (a) from about 1% to about 90% by weight of polyethylene oxides having a weight average molecular weight of from about 65,000 daltons to about 8,000,000 daltons; (b) from about 1% to about 40% by weight of polyethylene glycols having a number average molecular weight of from about 500 daltons to about 20,000 daltons; and (c) from about 9% to about 59% by weight of a biodegradable polymer.
The present invention is also directed to a method of making flushable tampon applicators wherein the method comprises (a) preparing a blended thermoplastic composition comprising (i) from about 1% to about 90% by weight of polyethylene oxides having a weight average molecular weight of from about 65,000 daltons to about 8,000,000 daltons; (ii) from about 1% to about 40% by weight of polyethylene glycols having a number average molecular weight of from about 500 daltons to about 20,000 daltons; and (iii) from about 9% to about 59% by weight of a biodegradable polymer and (b) injection molding the blended thermoplastic composition into molded thermoplastic components used to construct the flushable tampon applicator.
It has been found that flushable tampon applicators can be made from a combination of thermoplastic materials, especially a blend of high molecular weight polyethylene oxides, low molecular weight polyethylene glycols, and biodegradable polymers such as aliphatic polyesteramides, to result in flushable tampon applicators that readily disintegrate in a septic tank such as a toilet and are easily disposed of with minimal or no environmental issues. The flushable tampon applicators of the present invention comprise a combination of water-dispersible and biodegradable thermoplastic polymers which provide for improved disposal properties of the applicators. These applicators are capable of being flushed down a toilet or any other sewage system without causing drainage problems such as clogging, and are capable of biodegradation disposal using commonly employed biodegradation means.